Method for slaking lime.



W. SCHULTHESS. METHOD FOR SLAKING LIME. APPLICATION FILED JAN.19,1912.

1,067,686. Patented July 15, 1913.

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WALTER SCHULTHESS, OF PARIS, FRANCE.

METHOD FOR SLAKING LIME.

Specification of Letters Patent.

'Application filed January 19, 1912. Serial No. 672,153.

To all whom it may concern Be it known that I, WVALTER SciiuL'ri-mss, acitizen of the Republic of Switzerland,

residing at Paris, France, have invented new and useful Improvements inMethods for Slaking Lime; and I do hereby declare the following to be afull, clear, and exact description of the invention, such as will enableothers skilled in the art to which it appertains to make and use thesame, reference being had to the accompanying drawings, and to lettersor figures of reference marked thereon, which form a part of thisspecification.

It has previously been proposed to conduct steam containing powderedlime, into water, said lime-containing steam resulting from slaking limein vertical chimneys, to the axis of which is admitted the slakingwater. By a series of conically shaped funnels mounted in the chimneythis lime-containing steam is alternately distributed and collected,being exposed to a water spray, and the product is used again to slakenew charges of lime. Experience has proven that no satisfactorycleansing of the steam can be obtained thereby. Also, under the bestconditions, it is impossible to condense, by the quantity of waternecessary to slake a given quantity of lime during a definite period oftime, even one-half of the steam produced during the slaking operation,and without condensing the steam carrying the powdered lime, it. isimpossible to completely precipitate the lime. These conditions arecaused by the steam entering the chimney at a very high temperature. Tocool the steam to condensation, a quantity of water becomes necessarywhich considerably exceeds the quantity of water necessary for slaking.Moreover, the lime water produced by the complete transformation of thepowdered lime contained in the steam will be transformed into alime-paste, which because of its physical qualities can not be conductedonto the lime to be slaked.

According to .my invention, steam containing powdered lime, produced byslaking a definite quantity of lime, hen leaving the slaking apparatusis conducted through a preferably horizontal channel, in which thegreater portion of the powdered lime, by reason of the specific weightof the lime, is precipitated in the form of a drypowder, and thetemperature of the steam is lowered so much that by a followingtreatment with well distributed water it is instantly con-- doused, sothat a complete precipitation of all the lime-powder contained in thesteam is secured. Byt-he device hereinafter described a heating of theslaking water to 180 F. is also obtained for continuousworking, whichmuch accelerates and improves the process of slaking.

In the accompanying drawing a device for carrying out my invention isillustrated by way of example.

Figure 1 shows a longitudinal section Patented July 15,1913.

through the device. Fig.' 2 a longitudinal section through a portion ofthe same, drawn to a larger scale. Fig. 3 is a cross-section on line A-Aof Fig. 2. Fig. 4 is a longitudinal section through another illustrativeembodiment of the discharge end of the device. Fig. 5 is a frontelevation showing the device illustrated in Fig. 1.

To irrigate the-lime to be slaked there is provided a pipe 3 whichextends to the interior of the retic-ulate drum 2. The drum is supportedat one end by the reticulate cross 4 provided with a long nave mountedon a shaft 25. At the other end, the drum rests on rollers 5 mountedinside the mantle of the slaking-vessel. The rollers 5 are guided in afurrow 6, Fig. 3, provided on the mantle of the reticulate drum. Theshaft 25 is disposed in the axis of the slaking-vessel 23 and carriesmixing and conveying blades 22. The slaking vessel is surrounded by asteamjacket 24:. The reticulate cross t is provided with holes 21through which the parts of the charge which cannot be slaked, as partsof unslaked lime and stones, in the slaking vessel may be forced out.

To the vertical chimney 8 is connected one end of a horizontal channel17 to the other end of which is connected a chimney 9 of a largerdiameter than the channel 17, and inside, in the axis of the chimney 9,are mounted a number of spraying nozzles 11. The nozzles 11 are fed by apipin 12 carrying water under high pressure, w ose atomized discharge isdispersed in the chimney 9 as a fine mist. The channel 17 is alsoprovided with a downward extending branch 18 with a closing device orvalve 19 for its opening, under which a receptacle, as a each 20, forinstance, can be arranged.

A large portion of the lime-powder con tained in the steam isprecipitated in the channel 17 and may be collected in the sack 20. Thislime-powder forms ahydrate of lime which is very pure and finelydispersed.

The steam escaping from the slaking vessel through the chimney 8 whichstill contains lime-powder, after its temperature is considerablylowered, is forced to pass through the mist which is formed in thechimney 9 by the nozzles 11, and condensed, and at the same time freedfrom the lime-powder. The water flowing downward on the walls of thechimney 9 is converted into lime-water and flows into a channel 9 fromwhence it is led back by the pipe 3 into the slakingvessel to be used asslaking water for new quantities of lime. The quantity of water enteringby pipe 12 is regulated so that the quantity of water flowing out of thenozzles during a definite period of time is exactly sufiicient to slakethe quantity of lime introduced in the slaking device during the saidperiod of time. By applying a horizontal channel 17 of a suitable size,all lime-powder can be precipitated and converted into a thin limevater. A large portion of the heat of the steam produced by slaking istransferred to the slaking water discharged from the nozzles 11, and thewater is thus heated to about 160 F. This is very important, becausesome kinds of lime can only be slaked with warm slaking-water.

In the illustrative embodiment shown in Fig. 4, a heavy angle iron 13 isprovided at the discharge end of the slaking-vessel. The angle ironmaintains on the bottom of the vessel a layer of slaked lime in the formof lime-Water and at a certain level, while the excess flows out. Piecesof unslaked lime and foreign materials are stopped by the angle iron andscooped up by cups l t mounted on the shaft 25, from which they arethrown on an inclined discharge plate 15. An opening 16 is provided inthe bottom of the vessel, and this opening, which is closed while theapparatus is in operation, serves for completely discharging theapparatus when desired.

In order to avoid rapid wear of the reticulate device, the reticulatedrum may be made of perforated sheets, instead of wiregauze. In thiscase, the thickness of the sheet must be such that the vibrations causedby the rotation of the reticulate drum, will prevent the choking of thelatter. The

sheets are suitably made from 0.08 to 0.5

inch thick, according to the nature of the lime to be slaked and thesize of the apparatus.

In carrying out my improved method, the lime to be slaked is filled intothe reticulate drum 4 to which slaking water is admitted. A preliminaryslaking is thus produced, which is continued in the slaking vessel 23.The steam produced, carrying the heat and lime powder originating fromthe slaking process, is conducted through the horizontal channel 17 inwhich the greater portion of the lime powder is precipitated as aconsequence of the rapid cooling of the steam. The cooled steam is thenconducted to the chimney 9 and into the path of the water used for theslaking process, and is condensed in the form of lime-water, which isused to slake new quantities of lime.

I claim- 1. Method for slaking lime, which consists in filling lime intoa slaking vessel, admit-ting Water to the vessel, mixing the water andlime, conducting the steam produced carrying heat and lime-powder into acooling channel in which the greater portion of the lime-powder isprecipitated in form of dry powder and the temperature of the steam islowered, exposing said steam to finely dispersed Water, and leading theresulting water containing some lime into the slaking vessel containingnew quantities of lime to-be slaked.

2. Method for slaking lime, which consists in slaking lime with water,conducting the resulting steam carrying lime-powder into a horizontalcooling channel in which the greater portion of the lime-powder isprecipitated in the form of dry powder and the temperature of the steamis lowered, exposing said steam to finely dispersed water and using theresulting water containing some lime for slaking fresh quantities oflime.

In testimony that I claim the foregoing as my invention, I have signedmy name in presence of two subscribing witnesses.

WALTER SCHULTHESS.

Witnesses:

ALPHONSE LoUIs. SToFFEL, H. C. Goxn.

